1. Field of the Invention
The present invention relates to an upper limb training device and, specifically, to an upper limb training device for exercise with multiple degrees of freedom of an upper limb, which is compact and easy to carry.
2. Description of the Related Art
Most conventional training devices use weights such as weight stacks combined with a training structure to provide resistance, to accomplish a goal of training. As the desired resistance increases, inertia forces also increases. This may cause sports injury if a user incautiously uses the training devices improperly. The minimum resistance value that this kind of training device provides is still too large for a patient who has trouble with muscle degeneration. In this case, the patient's goal of training cannot be accomplished, or the use of this kind of training device may cause other injury. The prior arts, such as U.S. Pat. No. 6,394,937, U.S. Pat. No. 7,601,187, and U.S. Pat. No. 7,670,269 all use elements such as weight stacks to provide resistance during training.
For example, in U.S. Pat. No. 6,394,937, a pulley system is used coupled to a handle portion of the device and weights such as weight stacks. When the user exercises by manipulating the handle portion, the weight stack provides resistance to exercise, to magnify the effect of exercise. The design of the structure or the process of adjusting resistance of this kind of device, however, is complicated. It is difficult for the user to select an optimal resistance value and adjust a resistance value to the optimal one during the exercise process.
Moreover, in prior arts, most muscle training devices only provide movements on a single plane or for a specific muscle group, and the devices are bulky. If the user wants to use a single training device to do exercise on multiple planes or for multiple muscle groups, he/she has to change components and assemble the device often. This takes time and energy. In addition, the user can only go to a place which has this kind of training device at a specific time to exercise, which makes the training more difficult and limited.
For example, U.S. Pat. No. 7,235,038 discloses a design specifically for elbow training in structure. Protectors able to rotate relative to one another are used and cooperate with resilient elements for providing resistance for exercise, such that the goal of building the user's arm is accomplished. However, the design is for exercising a single muscle group. If the user wants to exercise other muscle groups, he/she has to use other training devices corresponding to other muscle groups. This can be troublesome.
In U.S. Pat. No. 4,772,015, a rod is pivotally connected with a resistance member. A user exercises his/her arm by grasping a hand grip assembly of the rod, and the resistance member is used to provide resistance when exercise is performed, such that the goal of building his/her arm is accomplished. However, due to the limit of the structure of the device, when the user wants to exercise his/her shoulder with multiple degrees of freedom, he or she has to adjust the position of the resistance member and to move the position of the whole device. This is inconvenient for use.
Therefore, it is desirable to provide an upper limb training device able to perform an arm exercise with multiple degrees of freedom with a single device. Also, the device has to allow for exercise or physical therapy anytime and to prevent injury that inertia forces may cause. Moreover, the device has to be easy to adjust and carry, and its use is not limited by space and place, to mitigate and/or obviate the aforementioned problems.